Robin A. Bruski, John M. Stewart, Wolf Research Team, Northland College, Ashland, WI 54806, USA

Over the past seven years, the Wolf Research Team has been conducting studies of the behavior and ecology of the wolf (Canis lupus) in northern Wisconsin, a forested area fragmented by rural agriculture and suburban development. At any given time, 30-60 animals in 8-10 wolf packs are under study. Members of the Wolf Research Team are organized into pack study groups of 2-4 individuals, each of which is assigned to study a particular wolf pack. Data on these animals are gathered by tracking surveys, howling surveys, and radio-telemetry monitoring.

The purpose of this paper is to report on the pattern and extent of infection of these northern Wisconsin timber wolf packs by internal parasites. These wolves occupy a fragmented habitat, where they may live in close proximity to humans and their domesticated dogs (Canis familiaris). Since they are very closely related, transmission of internal parasites from dogs could contribute significantly to the pattern of infection in wolf packs living in this kind of habitat.

During both the 1997-98 and the 1998-99 tracking seasons, samples of any scat found in the various wolf pack territories were collected as part of the routine survey protocol. Individual samples were double-bagged in plastic at the collection site, along with a scat sample form, which contained information on date, location, age and appearance (diameter, segment length, contents) at time of collection, the pack territory in which the sample was found, and other pertinent evidence (e.g. nearby tracks) that the scat had been deposited by wolves. Samples were frozen until ready to be analyzed. Thawed samples were subdivided, the sub-sample least exposed to environmental factors being selected for fecal flotation processing and identification of parasite eggs by microscopic examination.

Twenty-three scat samples from the 1997-98 tracking season were analyzed. Positive evidence for four different parasites were found: roundworms (Toxicara canis), tapeworms (Diplyidium caninum), hookworms (Ancylostoma caninum), and canine coccidia (Isospora bigemina). Thirty-four scat samples from the 1998-99 tracking season were analyzed. Positive evidence for six different parasites were found: roundworms, tapeworms, hookworms, whipworms (Trichuris vulpis), threadworms (Strongyloides stercoralis), and a trematode (fluke) parasite (Alaria).

As expected, roundworms were the most frequently found parasite. This is the most common internal parasite, infecting all the canid species. Nevertheless, the majority of scat samples tested negative for intestinal parasites, indicating an overall low level of infection in these wolves. This low level of infection, along with the wide variety of parasite species found, augurs well for the continued maintenance of genetic resistance to intestinal parasites in the northern Wisconsin timber wolf population.